Effects of visual flicker on subjective time in a temporal bisection task

This experiment investigated the effects of visual flicker on subjective time in humans using a temporal bisection task. A 200-800 ms duration range and 400-1600 ms duration range were presented. Each duration range was presented separately in three different conditions: (1) filled stimuli were presented in both the training and the testing phases, (2) flickering stimuli were presented in the training phase and filled stimuli were presented in the testing phase, and (3) filled stimuli were presented in the training phase and flickering stimuli were presented in the testing phase. Psychophysical functions displacements and bisection point values suggested that flicker increased the speed of the clock; however the direction of the displacement and bisection point changes depended on the phase of the task in which the flicker was presented. This result agrees with the specific storage in either working or reference memory components of Scalar Expectancy Theory of the increased number of pulses from the clock. Weber fractions and difference limens suggested that flicker did not affect subjects' temporal sensitivity. (C) 2008 Elsevier B.V. All rights reserved.